Molecular Weight Calibration of Asphaltenes Using Gel Permeation Chromatography/Mass Spectrometry

and, Shinya Sato; Takanohashi, Toshimasa; Tanaka, Ryuzo

doi:10.1021/ef049672r

Cited by 65 publications

(59 citation statements)

References 17 publications

(32 reference statements)

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“…On the other hand, a significant number of LDI investigations have concluded that asphaltenes are considerably heavier, with MWD peaking at 1500–2000 amu or above, and extending to several thousand amu 27–29. These latter results are typically in agreement with measurements based on vapor pressure osmometry27, 34, 39 and gel permeation or size–exclusion chromatography 11, 29, 30…”

Section: Introductionsupporting

confidence: 71%

“…The complexity and heterogeneity of asphaltenes has become a defiant benchmark for analytical techniques. Therefore, this topic has motivated intense experimental efforts in the past years22–40 and, not surprisingly, it has also constituted a source of constructive controversy around the potentiality and limitations of the different experimental methods and the interpretation of the observations.…”

Section: Introductionmentioning

confidence: 99%

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Laser desorption/ionization determination of molecular weight distributions of polyaromatic carbonaceous compounds and their aggregates

et al. 2007

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Molecular weight distributions (MWDs) of model polyaromatic hydrocarbons (PAHs) and complex asphaltene samples have been investigated in laser desorption/ionization mass spectrometry (LDI-MS)experiments. Special efforts are devoted to the characterization of aggregation effects during the desorption process. It is found that non-covalent clusters of the PAHs and asphaltenes form readily in the desorbing plume. Aggregation is favoured in the experiments performed on dense samples at high laser energy and under continuous ion extraction conditions. In the absence of polar groups in the analyte molecules, the aggregation propensity correlates well with the size of the polycondensed system and with its degree of pericondensation, in qualitative agreement with previous theoretical predictions. For the polydispersed asphaltenes from two different crude oils, MWDs peaking at masses smaller than 500 amu with a highmass tail extending up to about 3000 amu have been observed, yielding average weights around 900 amu. Such MWDs are in good agreement with previous mass spectrometric measurement, as well as with diffusion studies in solution. In addition, stable asphaltene aggregates have been detected giving rise to two broad bands in the mass spectrum corresponding to average molecular weights of 2200-3100 amu and 15 000-19 000 amu, respectively. It is concluded that the strong aggregation propensity of asphaltenes is likely to be responsible for the apparent inconsistency between the MWD for these compounds determined by different groups in independent LDI-MS experiments. The reliability of different sample preparation procedures, including solvent-free methods, is discussed, and strategies are outlined that serve to apply the potentiality of LDI mass spectrometry to the characterization of covalent and non-covalent compounds in complex carbonaceous systems.

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Section: Introductionsupporting

confidence: 71%

Section: Introductionmentioning

confidence: 99%

Laser desorption/ionization determination of molecular weight distributions of polyaromatic carbonaceous compounds and their aggregates

et al. 2007

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“…Size-exclusion chromatography (SEC) could also obtain a higher asphaltene molecular weight value than that from MS due to the association phenomenon. However, a more precise average MW can be obtained when using calibration curves on the basis of chemicals that better mimic the chemical functionalities of real petroleum fractions instead of conventional polymer standards [27,75,76]. Fluorescence decay and depolarization were once used to measure the molecular size and weight of asphaltenes by calibrating with known compounds [77,78].…”

Section: Sequential Elution Fractionation (Sef)mentioning

confidence: 99%

Fractionation and Characterization of Petroleum Asphaltene: Focus on Metalopetroleomics

et al. 2020

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Asphaltenes, as the heaviest and most polar fraction of petroleum, have been characterized by various analytical techniques. A variety of fractionation methods have been carried out to separate asphaltenes into multiple subfractions for further investigation, and some of them have important reference significance. The goal of the current review article is to offer insight into the multitudinous analytical techniques and fractionation methods of asphaltene analysis, following an introduction with regard to the morphologies of metals and heteroatoms in asphaltenes, as well their functions on asphaltene aggregation. Learned lessons and suggestions on possible future work conclude the present review article.

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“…Size exclusion chromatography (SEC), also referred to as gel permeation chromatography (GPC), separates molecules according to their linear molecular size, based on their distribution between a stationary phase of controlled pore size distribution and a liquid mobile phase. 28 Hence, longer molecules elute faster than shorter molecules. The SEC chromatograms obtained define the change in UV signal against molecular size in relation to molar mass.…”

Section: Molar Mass Distribution Of the Productsmentioning

confidence: 99%

Centrifugal Reactive-Molecular Distillation from High-Boiling-Point Petroleum Fractions. 2. Recent Experiments in Pilot-Scale for Upgrading of a Heavy Feedstock

Tovar

Winter

Wolf-Maciel

et al. 2013

Ind. Eng. Chem. Res.

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This work deals with the development of experimental campaign to accomplish the upgrading of a high-boilingpoint petroleum fraction (atmospheric residue ATR-W 673.15 K + with API gravity equals 11.9 and molar mass equals 2956 kg·kmol −1 ) by centrifugal reactive-molecular distillation (CRMD). In this process, 30 fractions (15 distillates and 15 residues) were obtained under different operating conditions. HT-SimDis GC played an important role to evaluate the conversion degree. Furthermore, physicochemical properties and colloidal characterization were determined by ASTM standard methods and size exclusion chromatography (SEC) with UV−absorption detection, respectively. The pilot-scale experiments by the CRMD process showed that it successfully upgraded the feedstock into two process streams named as distillate and residue streams using 3 and 5 wt % of zeolite-based catalyst at 483.15 K and pressure system below 50.0 Pa. Under these conditions, in the distillate streams the conversion of ATR-W 673.15 K + was found considerably higher (65.6% at 3 wt % of catalyst and 64.3% at 5 wt % of catalyst) than that of residue stream (49.6% at 3 wt % of catalyst and 53.1% at 5 wt % of catalyst). Moreover, it was found that distillate streams exhibited values of API gravity between 19 and 21 and molar mass up 200 kg·kmol −1 . To analyze residue streams values of API gravity were approximately equal to 11.9 and molar mass between 2570 kg·kmol −1 and 2908 kg·kmol −1 . In this respect, the CRMD process was successfully applied in order to upgrade a high-boiling-point petroleum fraction into lower boiling point products (corresponding to the distillate and residue streams).

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Molecular Weight Calibration of Asphaltenes Using Gel Permeation Chromatography/Mass Spectrometry

Cited by 65 publications

References 17 publications

Laser desorption/ionization determination of molecular weight distributions of polyaromatic carbonaceous compounds and their aggregates

Laser desorption/ionization determination of molecular weight distributions of polyaromatic carbonaceous compounds and their aggregates

Fractionation and Characterization of Petroleum Asphaltene: Focus on Metalopetroleomics

Centrifugal Reactive-Molecular Distillation from High-Boiling-Point Petroleum Fractions. 2. Recent Experiments in Pilot-Scale for Upgrading of a Heavy Feedstock

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